.gitignore: ignore link if target is included from feed

If an out of tree target is included via a feed, then there is a link with
the name 'feed' in the target directory. Do not show this link in git.

Signed-off-by: Florian Eckert <fe@dev.tdt.de>
(cherry picked from commit 13e7a2d19f4545170a8deaab03411bc37182f7c4)

.gitignore

@@ -14,6 +14,7 @@
 /feeds
 /feeds.conf
 /files
+/target/linux/feeds
 /overlay
 /package/feeds
 /package/openwrt-packages